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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

Artifact 813c37719866c583e6ca7660f94f10230f4e385d:


/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.32 2002/01/06 17:07:40 drh Exp $
*/
#include "sqliteInt.h"

/*
** This routine is call to handle SQL of the following forms:
**
**    insert into TABLE (IDLIST) values(EXPRLIST)
**    insert into TABLE (IDLIST) select
**
** The IDLIST following the table name is always optional.  If omitted,
** then a list of all columns for the table is substituted.  The IDLIST
** appears in the pColumn parameter.  pColumn is NULL if IDLIST is omitted.
**
** The pList parameter holds EXPRLIST in the first form of the INSERT
** statement above, and pSelect is NULL.  For the second form, pList is
** NULL and pSelect is a pointer to the select statement used to generate
** data for the insert.
*/
void sqliteInsert(
  Parse *pParse,        /* Parser context */
  Token *pTableName,    /* Name of table into which we are inserting */
  ExprList *pList,      /* List of values to be inserted */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  IdList *pColumn       /* Column names corresponding to IDLIST. */
){
  Table *pTab;          /* The table to insert into */
  char *zTab;           /* Name of the table into which we are inserting */
  int i, j, idx;        /* Loop counters */
  Vdbe *v;              /* Generate code into this virtual machine */
  Index *pIdx;          /* For looping over indices of the table */
  int srcTab;           /* Date comes from this temporary cursor if >=0 */
  int nColumn;          /* Number of columns in the data */
  int base;             /* First available cursor */
  int iCont, iBreak;    /* Beginning and end of the loop over srcTab */
  sqlite *db;           /* The main database structure */
  int openOp;           /* Opcode used to open cursors */
  int keyColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */

  if( pParse->nErr || sqlite_malloc_failed ) goto insert_cleanup;
  db = pParse->db;

  /* Locate the table into which we will be inserting new information.
  */
  zTab = sqliteTableNameFromToken(pTableName);
  if( zTab==0 ) goto insert_cleanup;
  pTab = sqliteFindTable(db, zTab);
  sqliteFree(zTab);
  if( pTab==0 ){
    sqliteSetNString(&pParse->zErrMsg, "no such table: ", 0, 
        pTableName->z, pTableName->n, 0);
    pParse->nErr++;
    goto insert_cleanup;
  }
  if( pTab->readOnly ){
    sqliteSetString(&pParse->zErrMsg, "table ", pTab->zName,
        " may not be modified", 0);
    pParse->nErr++;
    goto insert_cleanup;
  }

  /* Allocate a VDBE
  */
  v = sqliteGetVdbe(pParse);
  if( v==0 ) goto insert_cleanup;
  if( (db->flags & SQLITE_InTrans)==0 ){
    sqliteVdbeAddOp(v, OP_Transaction, 0, 0);
    sqliteVdbeAddOp(v, OP_VerifyCookie, db->schema_cookie, 0);
    pParse->schemaVerified = 1;
  }

  /* Figure out how many columns of data are supplied.  If the data
  ** is coming from a SELECT statement, then this step has to generate
  ** all the code to implement the SELECT statement and leave the data
  ** in a temporary table.  If data is coming from an expression list,
  ** then we just have to count the number of expressions.
  */
  if( pSelect ){
    int rc;
    srcTab = pParse->nTab++;
    sqliteVdbeAddOp(v, OP_OpenTemp, srcTab, 0);
    rc = sqliteSelect(pParse, pSelect, SRT_Table, srcTab);
    if( rc || pParse->nErr || sqlite_malloc_failed ) goto insert_cleanup;
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;
  }else{
    assert( pList!=0 );
    srcTab = -1;
    assert( pList );
    nColumn = pList->nExpr;
  }

  /* Make sure the number of columns in the source data matches the number
  ** of columns to be inserted into the table.
  */
  if( pColumn==0 && nColumn!=pTab->nCol ){
    char zNum1[30];
    char zNum2[30];
    sprintf(zNum1,"%d", nColumn);
    sprintf(zNum2,"%d", pTab->nCol);
    sqliteSetString(&pParse->zErrMsg, "table ", pTab->zName,
       " has ", zNum2, " columns but ",
       zNum1, " values were supplied", 0);
    pParse->nErr++;
    goto insert_cleanup;
  }
  if( pColumn!=0 && nColumn!=pColumn->nId ){
    char zNum1[30];
    char zNum2[30];
    sprintf(zNum1,"%d", nColumn);
    sprintf(zNum2,"%d", pColumn->nId);
    sqliteSetString(&pParse->zErrMsg, zNum1, " values for ",
       zNum2, " columns", 0);
    pParse->nErr++;
    goto insert_cleanup;
  }

  /* If the INSERT statement included an IDLIST term, then make sure
  ** all elements of the IDLIST really are columns of the table and 
  ** remember the column indices.
  **
  ** If the table has an INTEGER PRIMARY KEY column and that column
  ** is named in the IDLIST, then record in the keyColumn variable
  ** the index into IDLIST of the primary key column.  keyColumn is
  ** the index of the primary key as it appears in IDLIST, not as
  ** is appears in the original table.  (The index of the primary
  ** key in the original table is pTab->iPKey.)
  */
  if( pColumn ){
    for(i=0; i<pColumn->nId; i++){
      pColumn->a[i].idx = -1;
    }
    for(i=0; i<pColumn->nId; i++){
      for(j=0; j<pTab->nCol; j++){
        if( sqliteStrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
          pColumn->a[i].idx = j;
          if( j==pTab->iPKey ){
            keyColumn = i;
          }
          break;
        }
      }
      if( j>=pTab->nCol ){
        sqliteSetString(&pParse->zErrMsg, "table ", pTab->zName,
           " has no column named ", pColumn->a[i].zName, 0);
        pParse->nErr++;
        goto insert_cleanup;
      }
    }
  }

  /* If there is no IDLIST term but the table has an integer primary
  ** key, the set the keyColumn variable to the primary key column index
  ** in the original table definition.
  */
  if( pColumn==0 ){
    keyColumn = pTab->iPKey;
  }

  /* Open cursors into the table that is received the new data and
  ** all indices of that table.
  */
  base = pParse->nTab;
  openOp = pTab->isTemp ? OP_OpenWrAux : OP_OpenWrite;
  sqliteVdbeAddOp(v, openOp, base, pTab->tnum);
  sqliteVdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
  for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
    sqliteVdbeAddOp(v, openOp, idx+base, pIdx->tnum);
    sqliteVdbeChangeP3(v, -1, pIdx->zName, P3_STATIC);
  }

  /* If the data source is a SELECT statement, then we have to create
  ** a loop because there might be multiple rows of data.  If the data
  ** source is an expression list, then exactly one row will be inserted
  ** and the loop is not used.
  */
  if( srcTab>=0 ){
    if( db->flags & SQLITE_CountRows ){
      sqliteVdbeAddOp(v, OP_Integer, 0, 0);  /* Initialize the row count */
    }
    iBreak = sqliteVdbeMakeLabel(v);
    sqliteVdbeAddOp(v, OP_Rewind, srcTab, iBreak);
    iCont = sqliteVdbeCurrentAddr(v);
  }

  /* Push the record number for the new entry onto the stack.  The
  ** record number is a randomly generate integer created by NewRecno
  ** except when the table has an INTEGER PRIMARY KEY column, in which
  ** case the record number is the same as that column.
  */
  if( keyColumn>=0 ){
    if( srcTab>=0 ){
      sqliteVdbeAddOp(v, OP_Column, srcTab, keyColumn);
    }else{
      sqliteExprCode(pParse, pList->a[keyColumn].pExpr);
    }
    sqliteVdbeAddOp(v, OP_MustBeInt, 0, 0);
  }else{
    sqliteVdbeAddOp(v, OP_NewRecno, base, 0);
  }

  /* If there are indices, we'll need the new record number again, so make
  ** a copy.
  */
  if( pTab->pIndex ){
    sqliteVdbeAddOp(v, OP_Dup, 0, 0);
  }

  /* Push onto the stack, data for all columns of the new entry, beginning
  ** with the first column.
  */
  for(i=0; i<pTab->nCol; i++){
    if( i==pTab->iPKey ){
      /* The value of the INTEGER PRIMARY KEY column is always a NULL.
      ** Whenever this column is read, the record number will be substituted
      ** in its place.  So will fill this column with a NULL to avoid
      ** taking up data space with information that will never be used. */
      sqliteVdbeAddOp(v, OP_String, 0, 0);
      continue;
    }
    if( pColumn==0 ){
      j = i;
    }else{
      for(j=0; j<pColumn->nId; j++){
        if( pColumn->a[j].idx==i ) break;
      }
    }
    if( pColumn && j>=pColumn->nId ){
      sqliteVdbeAddOp(v, OP_String, 0, 0);
      sqliteVdbeChangeP3(v, -1, pTab->aCol[i].zDflt, P3_STATIC);
    }else if( srcTab>=0 ){
      sqliteVdbeAddOp(v, OP_Column, srcTab, i); 
    }else{
      sqliteExprCode(pParse, pList->a[j].pExpr);
    }
  }

  /* Create the new record and put it into the database.
  */
  sqliteVdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0);
  sqliteVdbeAddOp(v, OP_Put, base, keyColumn>=0);
  
  /* Create appropriate entries for the new data row in all indices
  ** of the table.
  */
  for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
    if( pIdx->pNext ){
      sqliteVdbeAddOp(v, OP_Dup, 0, 0);
    }
    for(i=0; i<pIdx->nColumn; i++){
      int idx = pIdx->aiColumn[i];
      if( idx==pTab->iPKey ){
        /* Copy the record number in place of the INTEGER PRIMARY KEY column */
        sqliteVdbeAddOp(v, OP_Dup, i, 0);
        continue;
      }
      if( pColumn==0 ){
        j = idx;
      }else{
        for(j=0; j<pColumn->nId; j++){
          if( pColumn->a[j].idx==idx ) break;
        }
      }
      if( pColumn && j>=pColumn->nId ){
        sqliteVdbeAddOp(v, OP_String, 0, 0);
        sqliteVdbeChangeP3(v, -1, pTab->aCol[idx].zDflt, P3_STATIC);
      }else if( srcTab>=0 ){
        sqliteVdbeAddOp(v, OP_Column, srcTab, idx); 
      }else{
        sqliteExprCode(pParse, pList->a[j].pExpr);
      }
    }
    sqliteVdbeAddOp(v, OP_MakeIdxKey, pIdx->nColumn, 0);
    sqliteVdbeAddOp(v, OP_IdxPut, idx+base, pIdx->isUnique);
  }


  /* If inserting from a SELECT, keep a count of the number of
  ** rows inserted.
  */
  if( srcTab>=0 && (db->flags & SQLITE_CountRows)!=0 ){
    sqliteVdbeAddOp(v, OP_AddImm, 1, 0);
  }

  /* The bottom of the loop, if the data source is a SELECT statement
  */
  if( srcTab>=0 ){
    sqliteVdbeAddOp(v, OP_Next, srcTab, iCont);
    sqliteVdbeResolveLabel(v, iBreak);
    sqliteVdbeAddOp(v, OP_Close, srcTab, 0);
  }
  sqliteVdbeAddOp(v, OP_Close, base, 0);
  for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
    sqliteVdbeAddOp(v, OP_Close, idx+base, 0);
  }
  if( (db->flags & SQLITE_InTrans)==0 ){
    sqliteVdbeAddOp(v, OP_Commit, 0, 0);
  }

  /*
  ** Return the number of rows inserted.
  */
  if( db->flags & SQLITE_CountRows ){
    sqliteVdbeAddOp(v, OP_ColumnCount, 1, 0);
    sqliteVdbeAddOp(v, OP_ColumnName, 0, 0);
    sqliteVdbeChangeP3(v, -1, "rows inserted", P3_STATIC);
    if( srcTab<0 ){
      sqliteVdbeAddOp(v, OP_Integer, 1, 0);
    }
    sqliteVdbeAddOp(v, OP_Callback, 1, 0);
  }

insert_cleanup:
  if( pList ) sqliteExprListDelete(pList);
  if( pSelect ) sqliteSelectDelete(pSelect);
  sqliteIdListDelete(pColumn);
}