Results of 1 - 10 of about 19 for Constraint (0.002 sec.)
- Information Schema 12738
- The views in the information_schema are SQL-standard views that describe the catalog entries of the database. These views can be filtered to obtain information about a specific column or table. DuckDB's implementation is based on PostgreSQL
...lable as of DuckDB 2.0. VARCHAR NULL New The is_generated and generation_expression columns were introduced in DuckDB 2.0. constraint_column_usage : Constraint Column Usage This view describes all columns in the current database that are used by some const...raint. For a check constraint, this view identifies the columns that are used in the check expression. For a not-null constraint, this view identifies t...he column that the constraint is defined on. For a foreign key constraint, this view identifies the columns that the foreign key references. For a uniqu... - https://man.mtool.work/duckdb/2.0/sql/meta/information_schema.html
- Constraints 12328
- In SQL, constraints can be specified for tables. Constraints enforce certain properties over data that is inserted into a table. Constraints can be specified along with the schema of the table as part of the CREATE TABLE statement . In cert
...ain cases, constraints can also be added to a table using the ALTER TABLE statement , but this is not currently supported for all constraints. W...arning Constraints have a strong impact on performance: they slow down loading and updates but speed up certain queries. Please consult the...Performance Guide for details. Syntax Check Constraint Check constraints allow you to specify an arbitrary Boolean expression. Any columns that do not satisfy this expression vi... - https://man.mtool.work/duckdb/2.0/sql/constraints.html
- Indexes 10074
- Index Types DuckDB has two built-in index types. Indexes can also be defined via extensions . Min-Max Index (Zonemap) A min-max index (also known as zonemap or block range index) is automatically created for columns of all general-purpose d
...ata types . Adaptive Radix Tree (ART) An Adaptive Radix Tree (ART) is mainly used to ensure primary key constraints and to speed up point and very highly selective (i.e., < 0.1%) queries. ART indexes can be created manually using the CRE...ATE INDEX clause and they are automatically created for columns with a UNIQUE or PRIMARY KEY constraint. Warning ART indexes must currently be able to fit in memory during index creation. Avoid creating ART indexes if the inde...ance, slowing down loading and updates, but speeding up certain queries. Please consult the Performance Guide for details. Constraint Checking in UPDATE Statements UPDATE statements on indexed columns and columns that cannot be updated in place are transfo... - https://man.mtool.work/duckdb/2.0/sql/indexes.html
- ALTER TABLE Statement 10074
- The ALTER TABLE statement changes the schema of an existing table in the catalog. Examples CREATE TABLE integers (i INTEGER, j INTEGER); Add a new column with name k to the table integers , it will be filled with the default value NULL : AL
...ER COLUMN i DROP DEFAULT; Make a column not nullable: ALTER TABLE integers ALTER COLUMN i SET NOT NULL; Drop the not- NULL constraint: ALTER TABLE integers ALTER COLUMN i DROP NOT NULL; Rename a table: ALTER TABLE integers RENAME TO integers_old; Rename a...integers RENAME i TO ii; Add a primary key to a column of a table: ALTER TABLE integers ADD PRIMARY KEY (i); Add a unique constraint to a column of a table: ALTER TABLE integers ADD UNIQUE (j); Syntax ALTER TABLE changes the schema of an existing table. A...COLUMN i TO j; ALTER TABLE integers RENAME i TO j; The RENAME [COLUMN] clause renames a single column within a table. Any constraints that rely on this name (e.g., CHECK constraints) are automatically updated. However, note that any views that rely on thi... - https://man.mtool.work/duckdb/2.0/sql/statements/alter_table.html
- CREATE TABLE Statement 10074
- The CREATE TABLE statement creates a table in the catalog. Examples Create a table with two integer columns ( i and j ): CREATE TABLE t1 (i INTEGER, j INTEGER); Create a table with a primary key: CREATE TABLE t1 (id INTEGER PRIMARY KEY, j V
...te primary key: CREATE TABLE t1 (id INTEGER, j VARCHAR, PRIMARY KEY (id, j)); Create a table with various different types, constraints and default values: CREATE TABLE t1 ( i INTEGER NOT NULL DEFAULT 0, decimalnr DOUBLE CHECK (decimalnr < 10), date DATE UN...t1 AS FROM t2 LIMIT 0; Note that only the column names and types are copied to t1 , other pieces of information (indexes, constraints, default values, etc.) are not copied. Temporary Tables Temporary tables are session scoped, meaning that only the specif...OM t2 WITH NO DATA; Or: CREATE TABLE t1 AS FROM t2 LIMIT 0; It is not possible to create tables using CTAS statements with constraints (primary keys, check constraints, etc.). Check Constraints A CHECK constraint is an expression that must be satisfied by... - https://man.mtool.work/duckdb/2.0/sql/statements/create_table.html
- DuckDB_% Metadata Functions 9476
- DuckDB offers a collection of table functions that provide metadata about the current database. These functions reside in the main schema and their names are prefixed with duckdb_ . The resultset returned by a duckdb_ table function may be
...r of open connections to the DuckDB instance. Column Description Type count The number of open connections. UBIGINT duckdb_constraints The duckdb_constraints() function provides metadata about the constraints available in the DuckDB instance. Column Descri...ption Type database_name The name of the database that contains the constraint. VARCHAR database_oid Internal identifier of the database that contains the constraint. BIGINT schema_name The SQL name of...the schema that contains the table on which the constraint is defined. VARCHAR schema_oid Internal identifier of the schema object that contains the table on which the constraint is... - https://man.mtool.work/duckdb/2.0/sql/meta/duckdb_table_functions.html
- Appender 8213
- The Appender can be used to load bulk data into a DuckDB database. It is available in the C, C++, Go, Java, Julia, Node.js, Python, and Rust clients. This page describes how the Appender behaves across clients and shows a minimal example in
...lock, which flushes on successful exit. Garbage collection discards any remaining buffered rows. See the Python Appender . Constraints such as NOT NULL , PRIMARY KEY , and UNIQUE are checked when the cache is flushed rather than as each row is added, so a...row can be accepted but later fail at flush time. See Handling Constraint Violations . Within a row, a value must be appended for every column of the table, in column order, before the row is ende...itly using transactions and surrounding your batches of appended rows by BEGIN TRANSACTION and COMMIT statements. Handling Constraint Violations If the Appender encounters a PRIMARY KEY conflict or a UNIQUE constraint violation, it fails and returns the fo... - https://man.mtool.work/duckdb/2.0/data/appender.html
- INSERT Statement 8076
- The INSERT statement inserts new data into a table. Examples Insert the values 1, 2, 3 into tbl : INSERT INTO tbl VALUES (1), (2), (3); Insert the result of a query into a table: INSERT INTO tbl SELECT * FROM other_tbl; Insert values into t
...ert the default value into a column: INSERT INTO tbl (i) VALUES (1), (DEFAULT), (3); Assuming tbl has a primary key/unique constraint, do nothing on conflict: INSERT OR IGNORE INTO tbl (i) VALUES (1); Or update the table with the new values instead: INSERT...CT Clause An ON CONFLICT clause can be used to perform a certain action on conflicts that arise from UNIQUE or PRIMARY KEY constraints. An example for such a conflict is shown in the following example: CREATE TABLE tbl (i INTEGER PRIMARY KEY, j INTEGER); I...NSERT INTO tbl VALUES (1, 42); INSERT INTO tbl VALUES (1, 84); This raises an error: Constraint Error: Duplicate key "i: 1" violates primary key constraint. The table will contain the row that was first inserted: SELEC... - https://man.mtool.work/duckdb/2.0/sql/statements/insert.html
- Appender 7478
- Appenders are the most efficient way of loading data into DuckDB from within the C interface, and are recommended for fast data loading. The appender is much faster than using prepared statements or individual INSERT INTO statements. Append
...er_flush Flush the appender to the table, forcing the cache of the appender to be cleared. If flushing the data triggers a constraint violation or any other error, then all data is invalidated, and this function returns DuckDBError. It is not possible to a...loses the appender by flushing all intermediate states and closing it for further appends. If flushing the data triggers a constraint violation or any other error, then all data is invalidated, and this function returns DuckDBError. Call duckdb_appender_er...it. By destroying it, this function de-allocates all memory associated with the appender. If flushing the data triggers a constraint violation, then all data is invalidated, and this function returns DuckDBError. Due to the destruction of the appender, it... - https://man.mtool.work/duckdb/2.0/clients/c/appender.html
- Appender 7478
- Use an appender to insert rows that your Python code produces. It collects rows and writes them together in one SQL statement; this is called flushing. The with block below flushes on successful exit: import duckdb con = duckdb.connect() co
...)) [('gadget', 0), ('widget', 10)] upsert runs an INSERT OR REPLACE , so the table needs exactly one primary key or unique constraint. It takes columns like an insert; on a conflict, only the listed columns change. update matches rows on the key columns an...arameter placeholders such as ? raise an exception at creation. These errors leave the transaction usable. Cast errors and constraint violations raise an exception during flush() . A flush that raises because an earlier result is still open or another call... - https://man.mtool.work/duckdb/2.0/clients/python/appender.html
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